vtkPolygonalSurfaceContourLineInterpolator 多边形曲面上的多边形绘制器

 【类简介】

在多边形曲面上实现轮廓点的交互绘制。

该类主要是实现在多边形曲面上绘制、移动轮廓点。该类插入的节点主要是用多边形数据来计算图像的测地距离，也就是说两点之间连线的是沿着几何表面的最短路径，使用Dijkstra算法。

该类的使用需要结合 vtkPolygonalSurfacePointPlacer 类，定位点的功能也就是拾取器。

前提：输入的多边形曲面需要计算法向量。

【示例】

</pre><pre code_snippet_id="1970532" snippet_file_name="blog_20161107_16_2205487" name="code" class="cpp">#include <vtkVersion.h>
#include "vtkSmartPointer.h"

#include "vtkActor.h"
#include "vtkCamera.h"
#include "vtkCellArray.h"
#include "vtkImageDataGeometryFilter.h"
#include "vtkPoints.h"
#include "vtkPolyData.h"
#include "vtkPolyDataCollection.h"
#include "vtkPolyDataMapper.h"
#include "vtkProperty.h"
#include "vtkRenderWindow.h"
#include "vtkRenderWindowInteractor.h"
#include "vtkRenderer.h"
#include "vtkSphereSource.h"
#include "vtkTriangleFilter.h"
#include "vtkXMLPolyDataReader.h"

#include "vtkContourWidget.h"
#include "vtkOrientedGlyphContourRepresentation.h"
#include "vtkPolygonalSurfacePointPlacer.h"
#include "vtkPolygonalSurfaceContourLineInterpolator.h"


int main(int argc, char *argv[])
{
  vtkSmartPointer<vtkPolyData> polyData;
  if (argc < 2)
    {
    vtkSmartPointer<vtkSphereSource> sphereSource = 
      vtkSmartPointer<vtkSphereSource>::New();
    sphereSource->SetThetaResolution(40);
    sphereSource->SetPhiResolution(20);
    sphereSource->Update();

    polyData = sphereSource->GetOutput();
    }
  else
    {
    vtkSmartPointer<vtkXMLPolyDataReader> reader = 
      vtkSmartPointer<vtkXMLPolyDataReader>::New();
    reader->SetFileName(argv[1]);
    reader->Update();
    polyData = reader->GetOutput();
    }

  // The Dijkistra interpolator will not accept cells that aren't triangles
  vtkSmartPointer<vtkTriangleFilter> triangleFilter = 
    vtkSmartPointer<vtkTriangleFilter>::New();
#if VTK_MAJOR_VERSION <= 5
  triangleFilter->SetInput( polyData );
#else
  triangleFilter->SetInputData( polyData );
#endif
  triangleFilter->Update();

  vtkSmartPointer<vtkPolyData> pd = triangleFilter->GetOutput();

  //Create a mapper and actor
  vtkSmartPointer<vtkPolyDataMapper> mapper = 
    vtkSmartPointer<vtkPolyDataMapper>::New();
  mapper->SetInputConnection(triangleFilter->GetOutputPort());

  vtkSmartPointer<vtkActor> actor = 
    vtkSmartPointer<vtkActor>::New();
  actor->SetMapper(mapper);
  actor->GetProperty()->SetInterpolationToFlat();

  // Create the render window, renderer and interactor.

  vtkSmartPointer<vtkRenderer> renderer = 
    vtkSmartPointer<vtkRenderer>::New();
  vtkSmartPointer<vtkRenderWindow> renderWindow = 
    vtkSmartPointer<vtkRenderWindow>::New();
  renderWindow->AddRenderer(renderer);
  vtkSmartPointer<vtkRenderWindowInteractor> interactor = 
    vtkSmartPointer<vtkRenderWindowInteractor>::New();
  interactor->SetRenderWindow(renderWindow);

  // Add the actors to the renderer, set the background and size

  renderer->AddActor(actor);
  renderer->SetBackground (.3, .4, .5);

  // Here comes the contour widget stuff...

  vtkSmartPointer<vtkContourWidget> contourWidget = 
    vtkSmartPointer<vtkContourWidget>::New();
  contourWidget->SetInteractor(interactor);
  vtkSmartPointer<vtkOrientedGlyphContourRepresentation> rep = 
    vtkOrientedGlyphContourRepresentation::SafeDownCast(
      contourWidget->GetRepresentation());
  rep->GetLinesProperty()->SetColor(1, 0.2, 0);
  rep->GetLinesProperty()->SetLineWidth(3.0);

  vtkSmartPointer<vtkPolygonalSurfacePointPlacer> pointPlacer =
    vtkSmartPointer<vtkPolygonalSurfacePointPlacer>::New();
  pointPlacer->AddProp(actor);
  pointPlacer->GetPolys()->AddItem( pd );
  rep->SetPointPlacer(pointPlacer);

  vtkSmartPointer<vtkPolygonalSurfaceContourLineInterpolator> interpolator =
    vtkSmartPointer<vtkPolygonalSurfaceContourLineInterpolator>::New();
  interpolator->GetPolys()->AddItem( pd );
  rep->SetLineInterpolator(interpolator);

  renderWindow->Render();
  interactor->Initialize();

  contourWidget->EnabledOn();

  interactor->Start();

  return EXIT_SUCCESS;
}